The school presented each of the veteran-graduates with a special medal.

Santa Clarita resident Nathaniel Smith joined the Marine Corps in 1997, choosing not to follow the family tradition of going into the medical field -- his family includes doctors and nurses.

"I have a white-collar mind and a blue-collar heart," Smith said.

The Marines trained him to work communications equipment.

"I got out and decided I didn't want that" as a civilian profession.

Since leaving the Marines in 2010, Smith drifted through a variety of jobs, including working on oil rigs and doing animal trapping, and picked up a psychology degree that he likewise has no interest in pursuing.

Instead, on Monday, he begins work as a diesel mechanic, giving him a mix of flexibility and good pay.

"I can go anywhere and do anything," Smith said. "I'm not bound to a dealership."

Tamaar Gradford actually was trained by the Marines to work on diesel engines, and he wanted no part of it back then.

The Moreno Valley resident joined the Marines in 2008, inspired by an Army veteran aunt and playing video-game soldier growing up.

"I came in as an open contract, which means they give you a random job," he said. "And the random job they gave me was diesel mechanic."

Diesel mechanic isn't what he had hoped for, and Gradford transferred into recon. But he soon realized he and his fellow Marines were risking their lives for relatively little pay.

"I wasn't comfortable being broke and having all of those adventures," he said.

Another Marine said all men either chase women, money or adventure, and Gradford realized he wanted to chase money. While in the Marines, he got accredited to work on an oil rig "" and one of those instructors said the best-paid money on those rigs were the diesel engineers, which led him back to being a diesel mechanic. Three weeks after his discharge, he was taking classes at UTI.

"Everything is way more thorough," he said. "In the military, you learn through experience."

In August, he plans to move to Arizona for more specialized training and then begin working on oil rigs and investing in real estate, with an eye toward retiring at 35, 11 years from now.

Like many veterans, Smith and Gradford appreciate the thanks from grateful civilians, but said that's not why they served.

"Most of us like a simple 'thanks' and a handshake goes far beyond," Smith said. "I'm very grateful that folks are grateful."